Cationic trirhenium rafts on. gamma. -Al sub 2 O sub 3 : Characterization by x-ray absorption spectroscopy

Journal Article · Thu Jan 10 04:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100154a045· OSTI ID:5774881

Fung, A S; Tooley, P A; Gates, B C ^[1]; Kelley, M J ^[2]; Koningsberger, D C ^[3]

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1. Univ. of Delaware, Newark (USA)
2. E.I. duPont de Nemours and Co., Wilmington, DE (USA)
3. Eindhoven Univ. of Technology (Netherlands)

Rhenium surface species, derived by treating (H{sub 3}Re{sub 3}(CO){sub 12}) adsorbed on {gamma}-Al{sub 2}O{sub 3} in hydrogen at 400{degree}C, formed extremely small surface grouping of rhenium atoms having an average Re-Re coordination number of 2, as determined by extended x-ray absorption fine structure (EXAFS) spectroscopy. Results of x-ray photoelectron spectroscopy and threshold resonance experiments show that the rhenium was cationic, with oxidation states of about +4 to +6. Infrared spectroscopy was used to follow the decomposition of surface species derived from (H{sub 3}Re{sub 3}(CO){sub 12}) adsorbed on {gamma}-Al{sub 2}O{sub 3}, the data indicating that Re subcarbonyls such as (Re(CO){sub 3}(O-Al){sub 2}(HO-Al)) were formed as intermediates. On the basis of the Re-O and Re-Re coordination parameters determined by EXAFS spectroscopy, a structural model of cationic trirhenium rafts on the {gamma}-Al{sub 2}O{sub 3} surface is suggested. This structure is characterized by a Re-Re distance of 2.67 {angstrom}, which is greater than the distances characterizing the quadruple and triple Re bonds (2.3 {angstrom}) in Re complexes but shorter than the distance in bulk metallic Re (2.74 {angstrom}). The Re-Re distance suggests an intermediate bond order, roughly 1.5.

• DOE Contract Number: FG02-87ER13790
• OSTI ID: 5774881
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:1; ISSN JPCHA; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
COMPLEXES
DATA
ELECTRON SPECTROSCOPY
EXPERIMENTAL DATA
INFORMATION
INFRARED SPECTRA
MEASURING METHODS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
RHENIUM COMPLEXES
SPECTRA
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
TRANSITION ELEMENT COMPLEXES